Wednesday, October 31, 2012

My blog has fallen into a state of disrepair as you can see. The infrastructure is crumbling and rusting away. I am not sure how much longer I can continue to operate on my dwindling power supply. But in any case...

Break out the costumes and candy, for today is the day when you get to dress up as whatever you like to celebrate all things strange and unusual. Make sure that the bowls of candy are filled for trick-or-treaters coming to your door, and do not skimp on the snacks or festivities for everybody else. I myself will be enjoying the evening watching the movie, Mr. Sardonicus, which is a classic that everybody should own.

For those of us who object to the celebration of Halloween on religious grounds, you must have had dull childhoods. Halloween is no more or less "pagan" than Christmas itself, which is a Christian re-branded version of the Roman holiday of Saturnalia. So, have a goodnight, everybody!

Thursday, January 19, 2012

Molten-salt reactors represent the most versatile and efficient types of reactors ever designed in the history of nuclear power engineering. Molten-salt reactors do not store their fuel in solid fuel rods. Instead, the nuclear fuel is chemically bonded with a halogen such as chlorine or fluorine to form a mineral salt. This mineral salt is liquid at the operating temperature of the reactor, which is pumped through the reactor systems. The molten salt mixture has a much higher operating temperature, allowing molten-salt reactors to take advantage of the Brayton cycle, and it is also unpressurized which removes the need for high pressure ductwork and allowing for a simpler reactor design. Conversely, it is impossible for these reactors to experience a meltdown since the fuel mixture is already molten and the density of the molten core decreases with increasing heat, and it pushes the amount of material needed to sustain critical mass out of the reactor core, slowing down the reaction.

There have been molten-salt reactors that have been built in the past as working experimental reactors, but there has yet to be an existing commercial example of an MSR-type reactor. The FUJI reactor project in Japan is a planned prototype that has been based on MSR technology, but funding for the project has been stalled at the moment. Of all of the Generation IV designs, the MSR reactors show the most promise.

1. Liquid Salt Very High Temperature Reactor (LS-VHTR)

This is a molten salt variant of the VHTR (Very High Temperature Reactor) design.

Liquid-Salt Very High Temperature Reactors are similar to the VHTRs discussed previously in part 7 of this series of posts, except that they have a liquid core instead of a solid core. The liquid core allows for a greater degree of control over the fission reaction as well as enabling more effective removal processes for the reaction poisons in the fission by-products. In addition, the liquid core achieves higher ratios of thermal efficiency because of its greater conductivity of heat compared to solid-cored reactors. Finally, the physical properties of the liquid core make a runaway fission event impossible because the liquid core expands when heated. If the core becomes overheated, it will expand to the point to where the core's density will be too low in order for fission to continue.

The core is contained within a housing where fission takes place and the entire core is submerged in a pool of molten salt to regulate the temperature of the reactor core. A heat exchanger removes excess heat from the pool of molten salt to maintain a stable equilibrium within the coolant pool.

As fission takes place in the reactor, heat from fission heats up the material in the core where the hot liquid is pumped out of the core chamber into a duct near the top of the core in the primary coolant loop. It is carried to a heat-exchanger where a secondary loop of molten-salt coolant is heated up and is then sent to the turbine and generator. The cooled down salt in the primary coolant loop returns to an intake at the bottom of the reactor core where it is then heated up again to complete the circuit.

Moderator Type: Graphite

Technology: Generation IV

Existing Examples:

Advantages:

2. Liquid Fluoride Thorium Reactor (LFTR)

This is an even more revolutionary reactor design than the LS-VHTR. The reactor has a core of molten salt rather than a solid core, except it uses thorium as its nuclear fuel rather than uranium. It is much more efficient in terms of fuel utilization than a traditional thorium-based reactor and it can also be used as a breeder to create more fuel. This reactor design is very flexible in terms of what types of radioisotopes it can use to carry out fission and could even use the spent material left over from LWRs as fuel. Finally, its high operating temperature could be used as a heat source for many industrial processes rather than having to rely on natural gas and could hypothetically be an economically viable source of hydrogen production.

The reactor design is similar to that of the LS-VHTR, except that a circuit at the bottom of the reactor core allows part of the molten salt to be diverted to a chemical processing plant for fuel breeding purposes and to remove reactor poisons. The reactor uses a gas turbine to take advantage of the Brayton cycle for higher thermal efficiencies instead of a steam turbine. Instead of being submerged in coolant, the core of the reactor has valve that is sealed by a plug of frozen material that would defrost in the event of the reactor overheating which would allow the molten salt to be dumped into an emergency holding tank for the molten salt to cool down and solidify in.

About Me

I have a background in human anatomy and biology in addition to formal training as an art student. Although I am not pursuing nuclear physics as a formal field of research, I have always been an avid hobbyist of nuclear technology as well as other topics of scientific study. After conducting research on energy demand and environmental awareness, I have decided to create a blog of my own in order to keep track of the upcoming developments in nuclear energy because it remains the most practical and least environmentally damaging energy source that is available to humanity today.
I welcome all comments, suggestions, and criticism from anybody who posts here. However, spam will be blocked and trolls will be mocked without mercy.

Visitors

Radio

Glossary (Under Construction)

Combustion - The process of burning a fuel combined with an oxidant to produce heat and other forms of energy.

Boiling Water Reactor - A type of Light Water Reactor that uses normal water as a neutron moderator and coolant. Water is heated by fuel core elements within the reactor vessel where it is boiled into steam. The steam is used to turn a turbine for energy. It is otherwise abbreviated as a "BWR".

BWR - Boiling Water Reactor

Electrostatic Force - This is the phenomenon which binds electrons to the nucleus of an atom. The electrostatic force prevents two atoms from becoming close enough to each other for their nuclei to fuse because the like charges of their orbiting electrons repel each other.

Georeactor Theory - A scientific theory in the field of geology that proposes that heavy radioactive elements have become concentrated in the Earth's core during its early geological history. They eventually reached critical mass and are undergoing nuclear fission, similar to the Oklo reactor in Gabon, Africa. This would explain how the Earth's interior is able to maintain its steady heat and magnetic output. However, this theory remains untested.

Isotope - An atom with more or fewer neutrons than the number of protons that it has. Most atoms of an element have the same number of neutrons as protons but isotopes are an exception.

Neutron - A subatomic particle within the nucleus of an atom that has a neutral charge. Free neutrons can also initiate a nuclear reaction within the nucleus of an atom. These free neutrons are also the fourth kind of Ionizing Radiation which is called Neutron Radiation.

Neutron Radiation - A type of Ionizing Radiation that consists of free Neutrons traveling at high speeds. These neutrons are what drive most forms of nuclear reactions. It can pose a danger to many life forms, and it can also cause materials to become radioactive through the process of Neutron Activation.

Nuclear Chain Reaction - A series of nuclear reactions initiated by the products of a previous Nuclear Reaction.

Nuclear Fission - The process of splitting an atom into two nuclei of daughter elements. When an atom is split, two daughter elements are created, releasing energy in the process. The masses of the two daughter nuclei added together will equal the mass of the original atom that they split, from in accordance with the Conservation of Mass theory. However, recent experiments have shown that a minute amount of mass is unaccounted for with the resulting nuclei as a portion of the original atom's mass was converted into kinetic energy.

Nuclear Force - The phenomenon that holds the neutron and proton particles together in an atom's nucleus. The nuclear forces of an atom are very strong compared with the Electrostatic Force.

Nuclear Fusion - The process of fusing the nuclei of two atoms together, which releases energy in addition to stray neutrons. This is how stars like our sun create heat, light, and other forms of radiation.

Nuclear Reaction - Changes in an atom's structure which concern particles within its nucleus as opposed to chemical reactions which affect only its valence electrons. One of four types of nuclear reactions can occur: Fission, Fusion, Neutron Capture, or Nuclear Decay.

Oklo Fossil Reactor - A naturally occurring "Nuclear Reactor in the Oklo uranium mine of Gabon, Africa. Approximately two billion years ago, groundwater seeped into the uranium deposits which acted as a "Neutron Moderator" which allowed the uranium-235 within the surrounding rock to undergo continuous Fission. The heat from the fission reaction eventually caused the groundwater to boil away which halted the fission reaction. When the rocks cooled down, groundwater flowed in again, causing fission to resume. This intermittent cycle of Criticality initiation and cool down continued for several thousand years and produced an average of one hundred kilowatts of energy per hour.

Proton - A subatomic particle that is positively charged. It is commonly found within the nucleus of an atom. Free protons are one of the products of β Decay.

Thorium - A naturally occurring radioactive element that is element 90 in the periodic table. Most of the thorium found in nature is Thorium-232, with the isotopes Th-234, Th-231, Th-230, Th-228, and Th-227 in varying degrees. Thorium-232 remains the isotope of interest because of its potential use for nuclear energy. In its pure form it is a silvery-white metal that tarnishes to black in contact with oxygen.

Turbine - A type of rotary engine that uses a working fluid as a means of harnessing the energy being collected.

Uranium - A naturally occurring, radioactive element in the periodic table. It is element 92, and is the